The Air Force, as well as many government agencies, utilizes protective radomes to enclose its multitude of land-based radar systems, worldwide. These radomes protect radar from extreme weather and environmental attack. They must perform this task, while being transparent to all specified radar frequencies. Furthermore, these radomes must minimize maintenance during a 25-year life and must be structurally resistant to damage from transportation-to-site, installation-handling, maintenance, abuse, environmental conditions, and long-term operations.
The current radome technology used by the Air Force is based upon a series of no-win design decisions made 30 years ago. The sandwich panels are made from a crude lay-up process, incorporating thin fiberglass skins and thermoset resins, with a foam core. This process, coupled with the thin skins and weak bonding to the foam core, commonly causes delamination of the skin from the core during transportation, installation, and maintenance. Furthermore, in order to allow the radar system to perform well in rain, these radomes must exhibit hydrophobic properties to prevent accumulation of a conductive sheet of water that negatively impacts radio frequency (RF) transparency. Therefore, radomes are typically coated with hydrophobic paints. Over time, ultraviolet (UV) exposure and air pollution typically attack the painted coatings, and gel coatings, of existing radomes, degrading the hydrophobic properties. This in turn leads to poor transparency of signals and marginal or unacceptable radar performance. This is addressed by continual repainting, a costly process which involves power washing of radomes, exposing a site to paint-debris waste. The cost of this periodic maintenance to the Air Force can run into hundreds of millions of dollars. Finally, a typical Air Force radome made with 30-year old design standards, not only requires regular painting maintenance, but is also prone to impact and wind damage, further requiring replacement of delaminated radome sections.